Need a hint
This card has a low mana value, forces each player to make a tough choice, and simply outclasses most of its brethren save for maybe Plaguecrafter
Not only does Gnaw to the Bone gain significantly more life than (most) previous life gain spells, consistently gaining 10 to 16 life each use, you can also find it reliably with your self-mill
I've dealt someone 10,000 damage by casting Deflecting Palm on Wheel of Misfortune, I've stolen the other 3 players' Sol Rings and cast my own to form the Sol Exodia which taps for mana, I have won with Hellkite Tyrant and 0 of my own artifacts
But they have been known to share that bounty around a little, and even within those colors, the idea of returning a card from graveyard to play has a staggering amount of depth
Sword of Feast and Famine The black-and-green Sword of Feast and Famine is one of the strongest of the MTG sword cycle